need to preserve original functions docstring (#593)

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ## [Unreleased]
 
 ### Fixed
+- Fixed Sphinx autodoc skipping class methods with custom decorators. [#518](https://github.com/IN-CORE/pyincore/issues/518)
 - Pyomo version fixed to fix indp solver failure [#585](https://github.com/IN-CORE/pyincore/issues/585)
 
 ### Changed

pyincore/decorators.py

@@ -1,12 +1,20 @@
+from functools import wraps
+
+
 def forbid_offline(func):
     """
     Custom decorator to forbid method interact with remote service in offline mode.
+
     Returns:
     """
 
+    @wraps(func)  # uses functools.wraps to preserve the original function's metadata.
     def wrapper(self, *args, **kwargs):
         if self.client.offline:
             raise ValueError("Service is not available in offline mode.")
         return func(self, *args, **kwargs)
 
+    # important! Custom decorator needs to preserve the original function's docstring
+    wrapper.__doc__ = func.__doc__
+
     return wrapper